Institute of Ecological Chemistry, Sustainable Chemistry and Energy Research, TU Braunschweig, Hagenring 30, 38106 Braunschweig, Germany.
ChemSusChem. 2009;2(10):921-6. doi: 10.1002/cssc.200900111.
During the operation of a microbial bioelectrochemical system, charge balance must be maintained between the anode and the cathode. In an ideal scenario, the charge balance would be realized by the unhindered migration of H(+) or OH(-). At the same time, any kind of diffusion (crossover) between both electrode compartments should be avoided. However, as several studies have demonstrated, the experimental reality does not match this ideal picture. Crossover processes occur and H(+)/OH(-) migration only plays an inferior role in the charge-balancing ion transfer, which results in significant losses in the performance of the microbial bioelectrochemical system. This Minireview summarizes the conflict of selectivity versus mobility and discusses principle strategies to cope with the resulting constraints, including pH-static operation and the use of different separator materials and membrane-free systems. Finally, we show that every setup compromises either selectivity or mobility, and no apparent ideal solution currently exists.
在微生物电化学系统运行过程中，必须保持阳极和阴极之间的电荷平衡。在理想情况下，电荷平衡将通过 H(+)或 OH(-)的无障碍迁移来实现。同时，应避免两种电极室之间的任何扩散（交叉）。然而，正如几项研究所示，实验现实与这种理想情况并不相符。交叉过程会发生，并且 H(+)/OH(-)迁移仅在电荷平衡离子转移中起次要作用，这导致微生物电化学系统的性能显著损失。本综述总结了选择性与迁移率之间的冲突，并讨论了应对由此产生的限制的主要策略，包括 pH 静态操作以及使用不同的隔离材料和无膜系统。最后，我们表明每种设置都牺牲了选择性或迁移率，目前没有明显的理想解决方案。
